1. Technical Field
The present invention relates to a liquid container.
2. Related Art
In order to contain various kinds of liquid, such as ink and drink, various kinds of containers and bags (hereinafter also referred to as a “liquid container”) have been used. Such a liquid container has been used for a liquid consumption apparatus, such as an ink jet printer, for example. Specifically, an ink pack, an ink cartridge, and the like which store ink to be charged into the liquid consumption apparatus are mentioned.
For example, JP-A-2008-207429 discloses an ink pack (liquid containing bag) which is removably attached to an ink jet printer and describes that the ink pack contains a film subjected to aluminum vapor deposition treatment.
On the other hand, JP-A-2006-272900, JPA-2010-221470, and JP-A-2012-11552 disclose ink cartridges to be connected to an ink jet printer and describe that an ink containing chamber which contains ink in the ink cartridge has an ink supply port for supplying the ink to a printer and an air introduction port for introducing the air into the ink containing chamber to keep the internal pressure inside the ink containing chamber at a suitable level.
The liquid contained in the above-described liquid container sometimes generates gas due to a chemical change of components contained therein. For example, when ink is used as liquid, gas is sometimes generated due to the decomposition of dyes contained in the ink or a chemical reaction of a base metal pigment, such as aluminum, and a solvent, such as water.
Therefore, when the liquid container having a sealing structure which is not provided with the air introduction port as in the ink pack described in JPA-2008-207429 is used, the container is sometimes greatly deformed or damaged due to temporarily generated gas.
On the other hand, the ink cartridges described in JP-A-2006-272900, JP-A-2010-221470, and JP-A-2012-11552 have the air introduction port for keeping the internal pressure inside the ink containing chamber at a suitable level. The air introduction port has a mechanism of taking the air thereinto when the ink in the ink containing chamber is consumed, so that the pressure inside the ink containing chamber becomes negative pressure and does not have a mechanism of discharging gas generated in the ink containing chamber. Therefore, even when the liquid container having the air introduction port as in the ink cartridges described in JP-A-2006-272900, JP-A-2010-221470, and JP-A-2012-11552 is used, the container is sometimes greatly deformed or damaged due to gas temporarily generated in the ink cartridge.